//============================================================================
//
//  This file is part of GPSTk, the GPS Toolkit.
//
//  The GPSTk is free software; you can redistribute it and/or modify
//  it under the terms of the GNU Lesser General Public License as published
//  by the Free Software Foundation; either version 3.0 of the License, or
//  any later version.
//
//  The GPSTk is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU Lesser General Public License for more details.
//
//  You should have received a copy of the GNU Lesser General Public
//  License along with GPSTk; if not, write to the Free Software Foundation,
//  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110, USA
//
//  Copyright 2004, The University of Texas at Austin
//  Dagoberto Salazar - gAGE ( http://www.gage.es ). 2007, 2008, 2011
//
//============================================================================

//============================================================================
//
//This software developed by Applied Research Laboratories at the University of
//Texas at Austin, under contract to an agency or agencies within the U.S.
//Department of Defense. The U.S. Government retains all rights to use,
//duplicate, distribute, disclose, or release this software.
//
//Pursuant to DoD Directive 523024
//
// DISTRIBUTION STATEMENT A: This software has been approved for public
//                           release, distribution is unlimited.
//
//=============================================================================

/**
 * @file ComputeLinear.hpp
 * This class computes linear combinations of GDS data.
 */

#ifndef GPSTK_COMPUTELINEAR_HPP
#define GPSTK_COMPUTELINEAR_HPP

#include "../gpstk/ProcessingClass.hpp"



namespace gpstk
{

/** @addtogroup DataStructures */
//@{


/** This class computes linear combinations of GDS data.
 *
 * This class is meant to be used with the GNSS data structures (GDS)
 * objects found in "DataStructures" class, and it is intended to be
 * used as a more flexible replacement for classes such as ComputePC.hpp.
 *
 * A typical way to use this class follows:
 *
 * @code
 *
 *      // Define a linear combination to compute PC using C1
 *   gnssLinearCombination pcComb;
 *   pcComb.header = TypeID::PC;
 *   pcComb.body[TypeID::C1] = +GAMMA_GPS/0.646944444;
 *   pcComb.body[TypeID::P2] = -1.0/0.646944444;
 *
 *
 *      // Define another linear combination to compute PC prefit
 *      // residual
 *   gnssLinearCombination prefitComb;
 *   prefitComb.header = TypeID::prefitC;
 *   prefitComb.body[TypeID::PC] = +1.0;
 *   prefitComb.body[TypeID::rho] = -1.0;
 *   prefitComb.body[TypeID::dtSat] = +1.0;
 *   prefitComb.body[TypeID::rel] = -1.0;
 *   prefitComb.body[TypeID::tropoSlant] = -1.0;
 *
 *
 *      // Object to compute linear combinations of data
 *      // Linear combinations will be computed in a FIFO basis
 *   ComputeLinear linear;
 *   linear.addLinear(pcComb);
 *   linear.addLinear(prefitComb);
 *
 *      // Load observation data
 *   RinexObsStream rin("ebre0300.02o");
 *
 *      // Loads precise ephemeris object with file data
 *   SP3EphemerisStore SP3EphList;
 *   SP3EphList.loadFile("igs11513.sp3");
 *
 *      // Sets nominal position of receiver
 *   Position nominalPos(4833520.3800, 41536.8300, 4147461.2800);
 *
 *      // Declare a MOPSTropModel object, setting the defaults
 *   MOPSTropModel mopsTM( nominalPos.getAltitude(),
 *                         nominalPos.getGeodeticLatitude(), 30);
 *
 *      // Object to compute the tropospheric data
 *   ComputeTropModel computeTropo(mopsTM);
 *
 *      // Declare a basic modeler
 *   BasicModel basic(nominalPos, SP3EphList);
 *
 *   gnssRinex gRin;
 *
 *   while(rin >> gRin)
 *   {
 *
 *      gRin >> basic >> computeTropo >> linear;
 *
 *         // Dump results
 *      gRin.body.dump(cout,1);
 *   }
 *
 * @endcode
 *
 * The "ComputeLinear" object will visit every satellite in the GNSS
 * data structure that is "gRin" and will compute the previously defined
 * linear combination (or combinations).
 *
 * When used with the ">>" operator, this class returns the same
 * incoming data structure with the results inserted in it. Be warned
 * that if a given satellite does not have the observations or data
 * required by the linear combination definition, such data will be
 * taken as zero.
 *
 * \warning If the "ComputeLinear" object has more than one linear
 * combination definition, they will be applied in the same order they
 * were added to the object, i.e. in a FIFO (First Input - First Output)
 * basis. Therefore, you must be mindful of combination order.
 *
 * @sa ComputeCombination.hpp, ComputePC.hpp, ModelObsFixedStation.hpp
 * and ModelObs.hpp, among others, for related classes.
 */
class ComputeLinear : public ProcessingClass
{
public:

    /// Default constructor
    ComputeLinear()
    {
        clearAll();
    };


    /** Common constructor
     *
     * @param linearComb   Linear combination to be computed.
     */
    ComputeLinear( const gnssLinearCombination& linearComb )
    {
        linearList.push_back(linearComb);
    };


    /** Common constructor
     *
     * @param list    List of linear combination definitions to compute.
     */
    ComputeLinear(const LinearCombList& list)
        : linearList(list)
    { };


    /** Returns a satTypeValueMap object, adding the new data generated
     *  when calling this object.
     *
     * @param time      Epoch corresponding to the data.
     * @param gData     Data object holding the data.
     */
    virtual satTypeValueMap& Process( const CommonTime& time,
                                      satTypeValueMap& gData )
    throw(ProcessingException);


    /** Returns a gnnsSatTypeValue object, adding the new data
     *  generated when calling this object.
     *
     * @param gData    Data object holding the data.
     */
    virtual gnssSatTypeValue& Process(gnssSatTypeValue& gData)
    throw(ProcessingException)
    {
        Process(gData.header.epoch, gData.body);
        return gData;
    };


    /** Returns a gnnsRinex object, adding the new data generated
     *  when calling this object.
     *
     * @param gData    Data object holding the data.
     */
    virtual gnssRinex& Process(gnssRinex& gData)
    throw(ProcessingException)
    {
        Process(gData.header.epoch, gData.body);
        return gData;
    };


    /// Returns the list of linear combinations to be computed.
    virtual LinearCombList getLinearCombinations(void) const
    {
        return linearList;
    };


    /// Clear all linear combinations.
    virtual ComputeLinear& clearAll(void)
    {
        linearList.clear();
        return (*this);
    };


    /** Sets a linear combinations to be computed.
     *
     * @param linear    Linear combination definition to compute.
     *
     * @warning All previous linear combinations will be deleted.
     */
    virtual ComputeLinear& setLinearCombination(
        const gnssLinearCombination& linear )
    {
        clearAll();
        linearList.push_back(linear);
        return (*this);
    };


    /** Sets the list of linear combinations to be computed.
     *
     * @param list    List of linear combination definitions to compute.
     *
     * @warning All previous linear combinations will be deleted.
     */
    virtual ComputeLinear& setLinearCombination(const LinearCombList& list)
    {
        clearAll();
        linearList = list;
        return (*this);
    };


    /** Add a linear combination to be computed.
     *
     * @param linear    Linear combination definitions to be added.
     */
    virtual ComputeLinear& addLinear(const gnssLinearCombination& linear)
    {
        linearList.push_back(linear);
        return (*this);
    };


    /// Returns a string identifying this object.
    virtual std::string getClassName(void) const;


    /// Destructor
    virtual ~ComputeLinear() {};


private:


    /// List of linear combinations to compute
    LinearCombList linearList;


}; // End class ComputeLinear

//@}

}  // End of namespace gpstk

#endif   // GPSTK_COMPUTELINEAR_HPP
